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| author | Guenter Roeck <[email protected]> | 2024-09-24 15:42:05 +0000 |
|---|---|---|
| committer | Andrew Morton <[email protected]> | 2024-09-26 21:01:43 +0000 |
| commit | a3344078101ceee46d14a93f7e3a3b91a55d215b (patch) | |
| tree | 226ce35a57854203dcc48e91b5c3773ba5159e82 /mm/filemap.c | |
| parent | tools: fix shared radix-tree build (diff) | |
| download | kernel-a3344078101ceee46d14a93f7e3a3b91a55d215b.tar.gz kernel-a3344078101ceee46d14a93f7e3a3b91a55d215b.zip | |
mm: make SPLIT_PTE_PTLOCKS depend on SMP
SPLIT_PTE_PTLOCKS depends on "NR_CPUS >= 4". Unfortunately, that
evaluates to true if there is no NR_CPUS configuration option. This
results in CONFIG_SPLIT_PTE_PTLOCKS=y for mac_defconfig. This in turn
causes the m68k "q800" and "virt" machines to crash in qemu if debugging
options are enabled.
Making CONFIG_SPLIT_PTE_PTLOCKS dependent on the existence of NR_CPUS does
not work since a dependency on the existence of a numeric Kconfig entry
always evaluates to false. Example:
config HAVE_NO_NR_CPUS
def_bool y
depends on !NR_CPUS
After adding this to a Kconfig file, "make defconfig" includes:
$ grep NR_CPUS .config
CONFIG_NR_CPUS=64
CONFIG_HAVE_NO_NR_CPUS=y
Defining NR_CPUS for m68k does not help either since many architectures
define NR_CPUS only for SMP configurations.
Make SPLIT_PTE_PTLOCKS depend on SMP instead to solve the problem.
Link: https://lkml.kernel.org/r/[email protected]
Fixes: 394290cba966 ("mm: turn USE_SPLIT_PTE_PTLOCKS / USE_SPLIT_PTE_PTLOCKS into Kconfig options")
Signed-off-by: Guenter Roeck <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Reviewed-by: Geert Uytterhoeven <[email protected]>
Tested-by: Geert Uytterhoeven <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Diffstat (limited to 'mm/filemap.c')
0 files changed, 0 insertions, 0 deletions